This is a continuation-in-part application of Ser. No. 866,558 filed Jan. 3, 1978.
This invention relates to a method and means for converting a water drive center pivot irrigation system to air drive.
Thousands of water drive center pivot irrigation systems are in operation with one of the most notable systems being manufactured by Valmont Industries, Inc. of Valley, Nebr. The Valmont water drive systems comprise a water drive cylinder which is mounted on each of the drive towers and which is connected to a trojan bar which engages at least one of the drive wheels so that operation of the water drive cylinder causes the drive wheel to be rotated a predetermined amount.
The water required to operate the cylinders is taken from the sprinkler pipeline at each individual drive tower or unit. The power developed by the individual drive cylinder is dependent upon the water pressure that is available at that particular drive unit. Due to the friction created within the water pipe as the water is pumped through the system, the water pressure available at the individual drive units decreases as the distance from the pivot point increases. It is apparent that those drive units usually requiring the most power have the least available water pressure and therefore the least power for propulsion. After the water has been used in the cylinder for the power stroke, it is discharged in an area relatively close to the drive unit which interferes with the traction of the drive wheels and detracts from the desired water application pattern on the crop.
In those areas where a relatively large amount of sand is pumped from the well with the water, higher maintenance costs are created by the abrasiveness of the sand in the valves and cylinders. Since the system depends upon water pressure for its propulsion, it cannot be moved without spraying water upon the ground it is moved over. This is a disadvantage where the system is to be moved over a crop that is ready to harvest. Further, the dependency of the system upon water pressure for propulsion eliminates the possibility of using "low pressure" sprinkler designs. This disadvantage is apparent in today's awareness of the cost and availability of energy.
If the owner of a water drive system is dissatisfied with the operation of the system due to the problems enumerated above, he must replace the system with an expensive electric drive such as that manufactured by Sargent Manufacturing Company of Othello, Wash. or the air drive system such as that previously manufactured by Sidney Manufacturing Company of Sidney, Nebr.
Therefore, it is a principal object of the invention to provide a method and means for converting a water drive center pivot irrigation system to air drive.
A still further object of the invention is to provide a method of converting a water drive center pivot irrigation system to air drive which requires no cutting, welding, structural or mechanical changes to the existing system.
A still further object of the invention is to provide a method and means for converting a water drive center pivot irrigation system to air drive whereby the water distribution pattern will be improved.
A still further object of the invention is to provide a method of converting a water drive center pivot irrigation system to air drive which prevents wasting water through the drive system.
A still further object of the invention is to provide a method of converting a water drive center pivot irrigation system to air drive to prevent the dumping of water from the drive system into the wheel tracks.
A still further object of the invention is to provide a method of converting a water drive center pivot irrigation system to air drive which permits the system to be moved through the field without the necessity of pumping water therethrough.
A still further object of the invention is to provide a method of converting a water drive center pivot irrigation system to air drive which is economical.
These and other objects will be apparent to those skilled in the art.